Background: Occupational burnout is associated with diminished psychological flexibility and higher emotional (EE) and uncontrolled eating (UE). Psychological flexibility could be a mediating factor between burnout and eating behaviour. Objectives: To investigate differences in eating behaviour between those with different levels of psychological flexibility, and the association of the interaction between psychological flexibility and occupational burnout with eating behaviour. Design: The participants were working women (n = 263), who took part in the randomized controlled health intervention trial. Analyses were performed in a cross-sectional setting at baseline. Methods: Eating behaviour was measured using the Three Factor Eating Behaviour Questionnaire-18 [which evaluates EE, UE and cognitive restraint (CR)], psychological flexibility using Acceptance and Action Questionnaire-II and occupational burnout using Bergen Burnout Indicator-15. Participants were divided into four groups based on the quartile points of psychological flexibility. Results: The EE of those who were inflexible was higher than that of those whose flexibility was high moderate (p = 0.013) and who were flexible (p = 0.001). The UE of those who were inflexible was higher than the UE in the other groups with higher flexibility [low moderate (p = 0.034), high moderate (p < 0.001), and flexible (p < 0.001)]. Psychological flexibility diluted the association between occupational burnout and EE and UE. Multivariate analysis of variances revealed that the combination of psychological flexibility and burn- out had a stronger association with the variances of EE and UE than psychological flexibility alone. Conclusions: Persons who are psychologically inflexible have higher EE and UE. Future studies should investigate if increasing psychological flexibility helps decrease EE and UE.